Answer:
7572 m/s
Explanation:
The force between two masses separated by a distance r is given as:

Where F is the attractive force between 2 masses, m1 and m2, r is the distance between the centres of the masses and G is the universal gravitation constant, which is 
The mass of the earth (
) is far greater than the mass of the sputnik (
). Therefore
. The mass of the sputnik is neglected, therefore:

But F is actually centripetal acceleration, a = v²/r

Because of the enormous expense of creating conditions aboard
a spacecraft in which astronauts can survive, and the huge extra
weight and expense of guaranteeing their safety.
Answer:
66.4 m
Explanation:
To solve the problem, we can use the length contraction formula, which states that the length observed in the reference frame moving with the object (the rocket) is given by

where
is the proper length (the length measured from an observer at rest)
v is the speed of the object (the rocket)
c is the speed of light
Here we know
v = 0.85c
L = 35.0 m
So we can re-arrange the equation to find the length of the rocket at rest:

Answer:
0.5 kg
Explanation:
The momentum of an object is defined as
p = mv
where
m is the mass
v is the velocity
In this problem we have,
v = 15 m/s is the velocity of the stone
p = 7.5 kg m/s is the momentum
Solving for m, we can find the mass of the stone:
